Billingsley hurt his elbow last August, didn't pitch after early September and decided to try rehabilitation and a platelet-rich plasma injection instead of major surgery. He had been fine until feeling pain last Friday in a bullpen session. An MRI showed the injury.

"I think he was pretty confident coming into the spring. He had a great winter and was able to throw," he said. "I think he was more confident than we were."

Mattingly said the Dodgers began to echo Billingsley's optimism in spring training. Billingsley bruised the index finger on his right hand during a bunting drill on March 15, slowing his return.

Billingsley is 81-61 with a 3.65 ERA in eight big league seasons, making him the longest-tenured Dodgers pitcher.

"I'm sure he's disappointed," Mattingly said.

Billingsley's jersey hung in his locker at Citi Field. The team said he wasn't at the ballpark.

Mattingly declined to say whether Dodgers management regretted not pushing Billingsley to have surgery last year.

"I can't really speak for the medical department," he said. "You can't make a guy do anything. The fact that it was working was encouraging to him."

The Dodgers began the day at 8-10, not quite what they expected after a major, high-priced overhaul that started late last season.